The present invention relates to a heating and pressurizing apparatus for use in mounting electronic components. Using the apparatus, an electronic component pre-bonded onto a circuit board in a flip chip manner via a bonding element that needs heating and pressurizing is pressurized and heated, thereby making the bonding element cured so that the electronic component is post-bonded. The invention also relates to an electronic component mounting apparatus equipped with the heating and pressurizing apparatus, as well as an electronic component mounting method.
In recent years, the flip-chip mounting of ICs has been rapidly becoming widespread with views to thinner and smaller circuit boards with the pervasion of portable information terminals. In addition, in SAW (Surface Acoustic Wave) devices used for mobile phones, the flip-chip mounting is also beginning to rapidly prevail.
However, for the flip-chip mounting technique, unlike the conventional mounting technique, various connection methods are available and the present situation is that companies in the art are employing various methods, while groping thereabout, in terms of intellectual property rights, reliability, and the like. Among these methods, there has been a rapid increase in cases where heating and pressurizing are involved in the process of post-bonding with adhesive, ACF, or the like from the aforementioned point of view. An example of such a conventional heating and pressurizing method is described below with reference to the accompanying drawings.
FIG. 9 is an explanatory view of the flip-chip mounting process using the conventional heating and pressurizing method. In FIG. 9, reference numeral 1 denotes a nozzle for holding an electronic component 8 by suction, numeral 4 denotes a heating part for curing a bonding element 9, and numeral 6 denotes a table part on which a circuit board 7 is to be placed. In such a constitution, the bonding element 9 is previously applied to a mounting portion on the circuit board 7 where the electronic component 8 is to be mounted, and the circuit board 7 with the bonding element 9 is fixed onto the table part 6. Then, the table part 6 moves, so that the mounting portion is placed just under the nozzle 1. After that, the nozzle 1 moves down so that the electronic component 8 is mounted to the mounting portion via the bonding element 9. Then, while the electronic component 8 is pressurized against the circuit board 7 by the nozzle 1, the bonding element 9 is cured by heat generation of the heating part 4.
With the flip-chip mounting by using a heating and pressurizing technique of the conventional method as described above, it takes about 7 seconds for the circuit board 7 in which the bonding element 9 has previously been applied to the electronic-component mounting portion to be carried into the flip-chip mounter. The electronic components 8 are then mounted in about 7 seconds per electronic component, and about 60 seconds are required for the heating and pressurizing time for curing the bonding element 9 in the mounting process. Afterwards, the next circuit board 7 takes 7 seconds to be carried into the mounter successively, and a similar production operation is iterated. Therefore, when one electronic component 8 is flip-chip-mounted onto one circuit board 7, the production cycle time for each circuit board 7 is about 74 seconds.
However, in the above conventional process, although electronic components can be flip-chip-mounted onto the circuit board with high precision and high speed in the flip-chip mounter, the production rate comes to an abrupt fall because the heating and pressurizing operation for curing the bonding element 9 is also executed in the flip-chip mounter, prolonging the time required for the whole mounting process.
The present invention has been developed to solve such issues. Therefore, an object of the invention is to provide a heating and pressurizing apparatus for use in mounting electronic components, as well as an electronic component mounting apparatus equipped with the heating and pressurizing apparatus, and an electronic component mounting method. The present invention is capable of increasing to a maximum the production cycle efficiency of the mounting apparatus for flip-chip-mounting electronic components onto the circuit board, and of improving the productivity of the whole flip-chip mounting line.
In accomplishing these and other aspects, according to a first aspect of the present invention, there is provided an electronic component mounting method for producing a plurality of circuit boards, in which an electronic component pre-bonded on each circuit board of the boards via a bonding element is heated and pressurized so as to be post-bonded. The method comprises pre-bonding the electronic component onto each circuit board by a first unit; and post-bonding the pre-bonded electronic component on the circuit board by a second unit which is separate from and independent of the first unit (i.e., they can operate at different rates).
According to a second aspect of the present invention, there is provided an electronic component mounting method according to the first aspect, wherein the pre-bonding and the post-bonding are executed simultaneously. A plurality of the pre-bonded circuit boards produced by the pre-bonding are stored in a storage container and fed to the post-bonding in units of the storage container.
According to a third aspect of the present invention, there is provided an electronic component mounting method according to the first aspect, wherein the pre-bonding and the post-bonding are executed simultaneously, and the pre-bonded circuit boards produced by the pre-bonding are fed to the post-bonding one by one.
According to a fourth aspect of the present invention, there is provided an electronic component mounting apparatus for producing a plurality of circuit boards, in which an electronic component pre-bonded (i.e., primarily-bonded) on each circuit board of the boards via a bonding element is heated and pressurized so as to be post-bonded (i.e., secondarily bonded). The apparatus comprises a pre-bonding unit for pre-bonding the electronic component onto each circuit board; and an electronic-component post-bonding unit which is separate from and independent of the pre-bonding unit and operates simultaneously with the pre-bonding unit. The post-bonding unit heats and pressurizes the pre-bonded electronic component so that the pre-bonded electronic component is post-bonded on the circuit board.
According to a fifth aspect of the present invention, there is provided an electronic component mounting apparatus according to the fourth aspect, further comprising a carrying unit for carrying the circuit board produced by the pre-bonding unit (with the electronic component pre-bonded thereon) from the pre-bonding unit to the post-bonding unit.
According to a sixth aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components, comprising a placement table for placing thereon a circuit board on which an electronic component has been pre-bonded via a bonding element applied onto the circuit board. The apparatus also comprises a mounting finishing unit which is provided separately from the placement table and which heats the electronic component pre-bonded onto the circuit board placed on the placement table and pressurizes the electronic component in a direction of thickness of the circuit board. Thus, the electronic component is post-bonded on the circuit board.
According to a seventh aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components according to the sixth aspect, wherein the mounting finishing unit comprises a pressurizing device which has a contact member having a contact surface to be brought into contact with the pre-bonded electronic component. The pressurizing device moves the contact member in the direction of thickness of the circuit board to press the pre-bonded electronic component against the circuit board. A heating device heats the contact member to post-cure the bonding element.
According to an eighth aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components according to the seventh aspect. The pressurizing device further comprises a parallelism adjuster for adjusting parallelism between the contact surface of the contact member and the pre-bonded electronic component; and a pressurizing-force adjuster for adjusting the pressurizing force of the contact member.
According to a ninth aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components according to any one of the sixth to eighth aspects. The placement table has a placement-table heating device which is movable in both X and Y directions each perpendicular to the direction of thickness of the circuit board and which serves an auxiliary role in curing the bonding element.
According to a tenth aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components according to any one of the seventh to ninth aspects. Assuming that the contact member, the heating device, and the pressurizing device are taken as one set, the mounting finishing unit has a plurality of sets of the contact member, the heating device, and the pressurizing device, each set being operative independently of one another.
According to an 11th aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components according to any one of the 7th to 10th aspects, wherein the heating device comprises a ceramic heater for reducing temperature-increasing time and cooling time.
According to a 12th aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components according to any one of the 6th to 11th aspects, wherein the mounting finishing unit further comprises a contamination-preventing member supply unit. When the contact member pressurizes the electronic component, the contamination-preventing member supply unit supplies a contamination preventing member for preventing a contact surface of the contact member from being contaminated by the bonding element so that the contamination preventing member is interposed between the contact surface and the electronic component.
According to a 13th aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components according to the 12th aspect, wherein the contamination preventing member is formed of a sheet material.
According to a 14th aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components according to any one of the 6th to 13th aspects, wherein the placement table is equipped with a fixing unit for positioning and fixing the circuit board.
According to a 15th aspect of the present invention, there is provided a heating and pressurizing apparatus for use in mounting electronic components according to any one of the 6th to 14th aspects, wherein the heating and pressurizing apparatus comprises a plurality of the units, assuming that the placement table and the mounting finishing unit are taken as each unit of the units.